Make Search class

src/shared/settings/Search.ts

@@ -0,0 +1,76 @@
+type Entries = { [name: string]: string };
+
+export type SearchJSON = {
+  default: string;
+  engines: { [key: string]: string };
+};
+
+export default class Search {
+  constructor(
+    public defaultEngine: string,
+    public engines: Entries,
+  ) {
+  }
+
+  static fromJSON(json: any): Search {
+    let defaultEngine = Search.getStringField(json, 'default');
+    let engines = Search.getObjectField(json, 'engines');
+
+    for (let [name, url] of Object.entries(engines)) {
+      if ((/\s/).test(name)) {
+        throw new TypeError(
+          `While space in the search engine not allowed: "${name}"`);
+      }
+      if (typeof url !== 'string') {
+        throw new TypeError(
+          `Invalid type of value in filed "engines": ${JSON.stringify(json)}`);
+      }
+      let matches = url.match(/{}/g);
+      if (matches === null) {
+        throw new TypeError(`No {}-placeholders in URL of "${name}"`);
+      } else if (matches.length > 1) {
+        throw new TypeError(`Multiple {}-placeholders in URL of "${name}"`);
+      }
+    }
+
+    if (!Object.keys(engines).includes(defaultEngine)) {
+      throw new TypeError(`Default engine "${defaultEngine}" not found`);
+    }
+
+    return new Search(
+      json.default as string,
+      json.engines,
+    );
+  }
+
+  toJSON(): SearchJSON {
+    return {
+      default: this.defaultEngine,
+      engines: this.engines,
+    };
+  }
+
+  private static getStringField(json: any, name: string): string {
+    if (!Object.prototype.hasOwnProperty.call(json, name)) {
+      throw new TypeError(
+        `missing field "${name}" on search: ${JSON.stringify(json)}`);
+    }
+    if (typeof json[name] !== 'string') {
+      throw new TypeError(
+        `invalid type of filed "${name}" on search: ${JSON.stringify(json)}`);
+    }
+    return json[name];
+  }
+
+  private static getObjectField(json: any, name: string): Object {
+    if (!Object.prototype.hasOwnProperty.call(json, name)) {
+      throw new TypeError(
+        `missing field "${name}" on search: ${JSON.stringify(json)}`);
+    }
+    if (typeof json[name] !== 'object' || json[name] === null) {
+      throw new TypeError(
+        `invalid type of filed "${name}" on search: ${JSON.stringify(json)}`);
+    }
+    return json[name];
+  }
+}